Kuiper belt (English: Kuiper belt), also known as Leonard Kuiper belt, also known as Kuiper belt, Kuiper belt and Kuiper belt, is a disk shaped area of dense celestial bodies located outside the orbit of Neptune (about 30 AU from the sun) in the solar system near the ecliptic plane,[1]The hypothesis of the Kuiper belt was first put forward by American astronomer Frederick Leonard. More than a decade later, Gerald Kuiper confirmed this view. The Kuiper belt is similar to the asteroid belt, but its scope is much larger. It is 20 times wider than the asteroid belt and 20 to 200 times heavier.[2]
Chinese name
Kuiper belt
Foreign name
Kuiper belt
Alias
Edgeworth Kuiper Belt, Cooper Belt, Cooper Belt, Cooper Belt, Keiper Belt[3]
Gerald·Kuiper (1905.12.7 – 1973.12.24), a Dutch born American astronomer, proposed that there was a belt region running by ice at the edge of the solar system. In memory of the discovery of Kuiper, this region was named "Kuiper Belt".
Discovery History
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In 1987, David Jowett, an astronomer who was working at MIT, became more and more confused about the "apparent emptiness of the outer solar system",[4]Using the telescopes at the Kite Peak National Observatory in Arizona and the Intercontinental Observatory in the Toloro Mountains in Chile, Juvit and Liu Lixing conducted their own searches in almost the same way as Clyde Tombaugh and Charles Koval, and compared with, after five years of searching.
On August 30, 1992, Zhu Weite and Liu Lixing announced the "discovery of candidate Kuiper Belt objects": asteroid 15760,[5]Half a year later, they found a second object in this area, (181708) 1993 FW.[6]
In August 2023, Kinki University of Japan issued a press release saying that researchers from Kinki University and the National Astronomical Observatory of Japan successfully reproduced multiple features of Kuiper Belt objects outside the orbit of Neptune using computer simulation, and the simulation results showed that there might be an unknown earth like planet in the outer edge of the solar system.The research results have been published in the international academic journal Astronomical Journal.[12]
position information
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The Kuiper Belt is located outside the orbit of Neptune in the solar system (about 30 astronomical units away from the sun), and it is a compact disk area of celestial bodies near the ecliptic.[2]
Structural organization
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In the most complete range, including the outermost area away from the center, the Kuiper Belt extends from about 30 AU to 55 AU.However, it is generally believed that the main part only extends from the 2:3 resonance region of 39.5 astronomical units to the 1:2 resonance region of 48 astronomical units.The Kuiper Belt is very thin, mainly concentrated within 10 degrees above and below the ecliptic plane, but there are still many objects scattered in a wider space several times larger.In short, it is more like a receptacle or doughnut than a ribbon, and this means that the Kuiper Belt has a 1.86 degree tilt to the plane of the ecliptic.[2]
Due to the existence of orbital resonance, Neptune has played an important role in the structure of the Kuiper belt.On the time scale compared with the age of the solar system, Neptune's gravity makes the celestial bodies in some orbits unstable, either sending them into the inner solar system or driving them into the discrete disk or interstellar space.This creates some blank areas in the Kuiper Belt similar to the Kirkwood gap in the asteroid belt.For example, at a distance of 40 to 42 astronomical units, no celestial body can exist stably in this range.At any time, the objects observed in this range are recently entered and will be moved out to other spaces.[7]
Classical Kuiper Belt Objects
It is about~42 to~48 astronomical units. Although Neptune's gravitational influence is insignificant, and celestial bodies can exist almost unaffected, this area is the so-called traditional Kuiper belt, and two-thirds of the Kuiper belt objects observed at present are here.[1][4]
Because the first Kuiper Belt object discovered in modern times is 1992 QB1, it is regarded as the prototype of this kind of object, and is called QB1 object in the classification of Kuiper Belt objects.[5][7]
The Kuiper belt of the system has always been a complex of two different groups. The first group is the "dynamic cold" group, which is more like a planet: the orbit is close to a circle, the eccentricity of the orbit is less than 0.1, and the inclination relative to the ecliptic is less than 10 degrees (their orbital plane is close to the ecliptic plane, without too much inclination).The second type is the "dynamically hot" group, whose orbit has a large tilt (up to 30 degrees).These two types have such a name, not because of the difference in temperature, but because of the small gas. When they become hot, their relative speed will increase[5]The two ethnic groups not only have different orbits, but also have different compositions. The cold ethnic groups are redder than the hot ones, suggesting that they were formed in different environments.The hot group is believed to have formed near Jupiter and then been ejected by the gas giant.On the other hand, although Neptune may have cleaned up the cold group when it migrated outward, it is believed that the cold group was formed closer to its current location, whether closer or farther away.[1]
resonance
When the orbital period of a celestial body has a clear ratio to Neptune (this situation is called average motion resonance), if their relative baseline is appropriate, they may be locked in the synchronous motion with Neptune to avoid being perturbed and making the orbit unstable.If the celestial body is in such a correct orbit, for example, Neptune will circle twice every three times around the sun. When it returns to its original position, Neptune will always travel half an orbit farther than it, because Neptune will circle 1.5 circles in its orbit at this time.This is the so-called 2:3 (3:2) orbital resonance. The semi major axis of this orbital feature is about 39.4 astronomical units, while the known 2:3 resonant objects, including Pluto and its satellites, have exceeded 200[8]
Track classification based on semi major axis.
The members of this family are all classified as small bodies of the Pluto.Many small Pluto objects, including Pluto, will cross the orbit of Neptune, but because of resonance, they will never collide with Neptune. Some of them, such as Eugene and Ixion, are large enough to be included in the class of Pluto like objects.[9]The small objects of the Pluto family have high orbital eccentricity, so they should not have been in their current position, but because Neptune's orbital migration was transferred here. The semi major axis of the 1:2 resonance (every time Neptune turns a circle, it completes half a circle) is equivalent to 47.7 astronomical units, but the sparse population is sometimes called twotino.The smaller resonance groups are 3:4, 3:5, 4:7 and 2:5 Neptune also has Trojans, which are located in the LfourAnd LfiveOn the stable point of gravity.Neptune Troy is sometimes called 1:1 resonance with Neptune.Neptune Troy is stable in their orbit, but different from being captured by Neptune, they are believed to be formed along the orbit.[7]
Kuiper Cliff
1: 2 The known quantity beyond resonance is very small, which seems to be a boundary, but it is still uncertain whether it is the boundary outside the traditional Kuiper belt or just a wide gap.The 2:5 resonance distance observed is about 55 AU, which is considered to be outside the traditional Kuiper Belt;However, a large number of objects between the traditional Kuiper Belt and the resonance belt have not been observed in prediction.[6]
The early Kuiper Belt model believed that the number of large objects beyond 50 astronomical units should increase by two orders of magnitude. Therefore, this sudden decline, known as the "Kuiper Cliff", was completely unexpected, and its reason is still unclear.Bernstein and Trilling et al. found that the evidence that objects with a diameter of 100 km or more did indeed suddenly decrease at a distance of 50 astronomical units was not a deviation caused by observation.The possible explanation is that the material at that distance is too scarce or too dispersed to grow into a larger celestial body;Or the subsequent process destroyed the already formed celestial bodies.[7]
Physical characteristics
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The Kuiper belt extends from about 30 AU to 55 AU, from the 2:3 resonance region of 39.5 AU to the 1:2 resonance region of 48 AU.The Kuiper Belt is very thin, mainly concentrated within 10 degrees above and below the plane of the ecliptic, but there are still many objects scattered in a wider space several times, which means that the Kuiper Belt is inclined 1.86 degrees to the plane of the ecliptic. Due to the existence of orbital resonance, Neptune has played a significant role in the structure of the Kuiper Belt.On the time scale compared with the age of the solar system, Neptune's gravity makes the celestial bodies in some orbits unstable, either sending them into the inner solar system or driving them into the discrete disk or interstellar space.This creates some blank areas similar to the Kirkwood gap in the asteroid belt in the Kuiper belt. For example, no celestial body can exist stably in this area at a distance of 40 to 42 astronomical units.At any time, the objects observed in this range are recently entered and will be moved out to other spaces.[7]
observation data
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On August 1, 2014, astronomers announced that they had discovered two new frozen objects in the Kuiper Belt at the edge of the solar system, which is the result of their use ofHubble Space TelescopeThe discovery was made only two weeks after the observation.The Kuiper Belt is believed to be the end of the solar system, and is full of icy micro planets with diameters ranging from a few kilometers to thousands of kilometers.The two celestial bodies discovered are about 6.4 billion kilometers away from the Earth, and their names are 1110113Y and 0720090F.[10]、
On January 19, 2006, New Horizons, the first spacecraft to explore the Kuiper Belt, was launched.This task was proposed by a team led by Alan Stern, chief researcher of Southwest Research Institute.The New Horizons spacecraft arrived at Pluto on July 14, 2015. If conditions permit, it will continue to study other yet undetermined Kuiper Belt objects.Any Kuiper Belt object chosen would be 40 and 90 kilometers (25 to 55 miles) in diameter, ideally white or gray, in contrast to Pluto's reddish color.
On October 15, 2014, NASA announced the discovery of some Kuiper Belt objects, which may become the research target of New Horizons.[8]
On January 1, 2019, EST, New Horizons flew over the Kuiper Belt asteroid 2014 MU named "Tianya Haijiao" at 43.4 AU from the sunsixty-nine。[11]
